Kulde, mørke og avstand: virkninger på mentale prosesser

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1 HMS-utfordringer i Nordområdene: Helse og arbeidsmiljø, mørke og avstand: virkninger på mentale prosesser Stein Knardahl Solstrand, april 2014 Valg av påvirkninger Arbeids Tid Måter å oppfatte påvirkninger Eksponering under arbeid Individegenskaper Kompetanse Evner Antakelser Holdninger Personlighetstrekk Fysiologisk predisposisjon Ulykker Feil Unnlatelser Helse Varighet Tid på døgnet Skift rotasjon Hvileperioder Mekaniske Psykologiske Sosiale Kjemiske Mekanismer Biologiske Psykologiske Sosiale Plager Sykdom Sykefravær Frafall Måltider Biologiske Produktivitet Fysiske Søvn og hvile Helse-relatert atferd Relasjon til familie Fritidsaktiviteter Output Effektivitet Problemløsning Motivasjon 1

2 KLIMA Heat loss Radiation All objects emit electromagnetic waves (radiation). Conduction = Heat transmission Skin in direct contact with medium with large heat transmission ability (conductivity). Water has 25 X higher heat transmission ability (conductivity) than air. This is the background for much quicker cooling in water. Holding a tool made of metal, one loses heat through the tool. Convection = Transport of heat by movement in surrounding medium Layer near skin is heated by conduction. When this layer is transported away, it is replaced by cold air (or water if submerged) which is heated. Heat is lost. Heat loss by evaporation of sweat Evaporation of water or other liquid requires energy. If vapour transported away (convection), energy is lost, i.e. one loses heat. Heat loss in respiration Inspiratory air is heated in the airways to body temperature (37 o C), expiratory air emits heat to the environment. 2

3 Adaptation to cold Reduce heat loss Stop sveating Reduce skin temperature Close temperature regulating vessels in skin. Produce heat Shivering Rapid, rythmic muscle contractions which produce heat. Adrenalin-stimulation of heat production in muscles The contribution of this mechanism not decided in humans. Activation of brown fat Sympathetic nervous activity activates brown fat or similar enzyme in muscle. Thyroxine (T4) or T3 increases metabolic rate The brain (hypothalamus) produces TSH which stimulates the thyroid gland to produce T4 and T3. Working in cold environments Effects of local cooling Effects of general cooling - Hypothermia 3

4 KLIMA Helse-problemer Cognitive functions in cold environments Moderate short-lasting cold Sympathetic nerve activity + adrenalin Ability to maintain attention (vigilance) Ability to respond quickly General effects on the central nervous system? Effects on nerves + muscles: abiliy for tasks demanding precise movements Distress ( freeze ) influence attention and concentration Shivering influence attention and concentration Afterdrop (hyperthermia ) after cooling Selective attention Strong long-lasting cold producing hypothermia Ability for parallell processing of information Severe hypothermia: general judgement Confusion However: Inadequate knowledge to conclude which temperature and duration of cold exposure for cognitive functions to be reduced 4

5 Research on adaptation to cold exposure: Physiology: mechanisms for adaptation Animal experiments Young healthy humans: submersion in water cold air, light clothing cold water in face/splash Medicine/physiology: mechanisms and treatment to increase the survivial of cells in conditions with low oxygen Work in the petroleum industry Work periods last > 8 hrs - fatigue Work at night - Shift work Not all employees are healthy and young Existing knowledge based on studies of students and soldiers 5

6 Diurnal rythms Circadian rythms KLIMA Tidsvindu: årstider Ising Is i sjøen Isfjell Krav til arbeidet Helse-problemer Arbeidsforhold Kvalitative krav Tidspress-Arb.tid AVSTAND Transport Logistikk SAR Uro - bekymring 6

7 Statfjord-undersøkelsen 1985 Palinkas & Suedfeld, The Lancet,

8 KLIMA Tidsvindu: årstider Ising Is i sjøen Isfjell Krav til arbeidet Helse-problemer Arbeidsforhold Kvalitative krav Tidspress-Arb.tid AVSTAND LYS-MØRKE POLARE ÅRSTIDER Transport Logistikk SAR Innelukket installasjon: kontroll lys-mørke Uro - bekymring Søvnmangel Deprimert-irritabel SAD Polar T3 syndr KLIMA AVSTAND LYS-MØRKE POLARE ÅRSTIDER Tidsvindu: årstider Transport Logistikk SAR Optimalisere bekledning Protected Ising workstations Is i sjøen Isfjell Perfekt planlegging, Krav til Buffer arbeidet bemanning, Perfekt HRM Seleksjon ansatte Helse-problemer Arbeidsforhold Kvalitative krav Tidspress-Arb.tid Uro - bekymring Søvnmangel Deprimert-irritabel SAD Polar T3 syndr 8